ELECTRONIC EXCITATION BY ELECTRON-IMPACT OF THE O-2 MOLECULE PHYSISORBED ON A METAL

The electronic excitation process by low energy electron impact is stu died theoretically for the case of O-2 molecules physisorbed on a mode l jellium metal (A1). The spin forbidden excitations to the a (1) Gamm a(g) and b (1) Sigma(g)(+) states are considered, Only the resonant co ntribution corresponding to the (2) Pi(g)O(2)(-) resonance, which domi nates at low energy in the free molecule is included in the present wo rk. The characteristics of this resonant process involving a resonant state hidden below the excitation threshold are analyzed; in contrast with the free molecule case, a very important excitation process occur s below the energy threshold. The dependence of the excitation process on the symmetries of the problem is also discussed. (C) 1996 American Institute of Physics.